Oligosaccharide derivatives in which the 4- and 6-hydroxyl groups in the non-reducing end-group thereof are unprotected, with the other hydroxyl groups being protected are described in Lilbigs Annalen der Chemie, pp. 1910-1919 (1983). In the oligosaccharide derivatives disclosed, the reducing end-group has a phenylglycosidic linkage.
Oligosaccharide derivative in which the 4- and 6-hydroxyl groups at the non-reducing end-group are distinguished from other hydroxyl groups and the reducing end-group has a p-nitrophenylglycosidic linkage or a p-aminophenylglycosidic linkage are described in JP-A-60-54395, JP-A-60-87297, and JP-A-61-63299 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"). These oligosaccharide derivatives are characterized in that only the 4- and 6-hydroxyl groups of the non-reducing end-group are protected.
No disclosure is found in any of the above-cited references with respect to polyacetyl oligosaccharide derivatives having hydroxyl groups at the 4- and 6-positions of their non-reducing end-group and a p-nitrophenylglycosidic linkage or a p-aminophenylglycosidic linkage at the reducing end-group.
Pentamers or heptamers of glucose having a detectable group, e.g., for a dye, at the reducing end-group are well known particularly in the field of clinical examination as described, e.g., in JP-A-53-12831, JP-A-60-54395, JP-A-60-78994, JP-A-60-237998, JP-A-61-83195, and JP-A 63-17895. However, syntheses of oligosaccharide derivatives having a functional group at each of the end groups that are different in function have not yet been reported.